The subject invention relates, generally, to pipe joint assemblies and to methods for making pipe joints and, more particularly, to a methods for joining multi-laminate pipes.
In many industries, large volumes of corrosive and/or hazardous chemicals are used on a daily basis. Transfer of these chemicals across industrial plant sites occurs through a variety of pipe systems designed to withstand the corrosive nature of the chemicals and prevent the release of hazardous liquids, gases, vapors, and other emissions. This is often accomplished by using steel pipe fitted with a thermoplastic liner. The steel pipe acts as a structural casing and provides protection for the thermoplastic liner. The thermoplastic liner is the containment material, preventing exposure of the steel pipe structure and the environment to the corrosive and/or hazardous chemicals.
Similarly, dual laminate pipe has also been used to transport corrosive and/or hazardous chemicals. Like lined steel pipe, dual laminate pipe consists of a structural casing that supports and protects a thermoplastic liner. However, the emergence and success of dual laminate pipe, which is, typically, the more expensive alternative, suggests that the dual laminate pipe has advantages over lined steel pipe. Among these advantages are a light weight; for example, the fiberglass-reinforced plastic (xe2x80x9cFRPxe2x80x9d) casing used as the outer laminate in many dual laminate pipes is four times lighter than steel. Furthermore, the outer laminate in the dual laminate pipe, typically, is more resistant to corrosion and other environmental effects than is steel and, unlike steel, requires no additional corrosion protection (e.g. painting). Another advantage of dual laminate pipe relates to the fact that the inner laminate (e.g., the thermoplastic liner) is fully bonded to the outer laminate (e.g., an FRP structure), which permits the dual laminate pipe to withstand exposure to vacuum even at elevated temperatures). Furthermore, use of dual-laminate pipe enables one to reduce the number of flanged joints required in the system, thus reducing the likelihood of emissions from flanged joints.
Despite these advantages of dual-laminate pipe, three distinctions sometimes make lined steel pipe an attractive alternative.
The first advantage relates to initial cost. The cost, in terms of materials and manpower, of producing dual laminate pipe is higher than that of lined steel pipe. However, since dual laminate pipe lasts from three to five times as long as lined steel pipe in the same applications, lifecycle costs can frequently justify the higher initial expenditure.
The second advantage relates to strength. The steel casing of lined steel pipe is capable of spanning greater lengths between supports. This reduces the number of structural locations and pipe supports required to properly install the lined steel pipe system. However, in most applications, the additional costs for extra support steel and other support devices needed to install dual-laminate pipe vis a vis lined steel pipe are actually minimal. Moreover, using a number of techniques developed to adapt dual laminate systems to existing pipe support structures designed for lined steel pipe systems, these additional costs turn out to be a very small percentage of the job""s total cost.
The third advantage relates to the ease of installation of lined steel vis a vis dual laminate pipe systems. Customers using a lined steel system are capable of making pipe sections themselves. They can prepare a steel pipe section by welding flanges on each end and then inserting a thermoplastic liner and flaring the liner material over the ends of the flanges. Currently, customers using dual laminate pipe systems must rely on the manufacturer to supply custom-made pipe sections. They must also rely on emergency service from the manufacturer should damage or failure occur. Until now there has been no method developed that allowed customers to prepare random length pipe sections for dual laminate pipe.
Accordingly, there exists a need for a method of joining sections of dual-laminate pipe. The present invention is directed to meeting this need.
The present invention relates to a method for sealing an end of a pipe to an external sealing surface. The method includes providing a pipe assembly which includes a pipe (such as a multi-laminate pipe) and a flange. The pipe includes a proximal pipe end and a flared end region. The flared end region is proximate to and continuous with the proximal pipe end. The flange is non-integrally disposed around the pipe distal to the pipe""s flared end region. The method further includes securing, non-integrally, distally, and loosely to the pipe""s flared end region, the flange to the pipe so that proximal movement of the flange relative to the pipe is restricted. The flange is drawn toward the external sealing surface, which causes the flange sealing surface to bias the pipe""s flared end region into sealing contact with the external sealing surface.
The present invention also relates to another method for sealing an end of a pipe to an external sealing surface. In this method a pipe assembly which includes a pipe and a flange is provided. The pipe is a multi-laminate pipe and includes a proximal pipe end and a flared end region. The flared end region is proximate to and continuous with the proximal pipe end. The flange is non-integrally disposed around the pipe distal to the pipe""s flared end region, and the flange is secured, non-integrally and distally to the pipe""s flared end region, to the pipe so that proximal movement of the flange relative to the pipe is restricted. The method further includes drawing the flange toward the external sealing surface, which causes the flange sealing surface to bias the pipe""s flared end region into sealing contact with the external sealing surface.
The present invention also relates to a pipe assembly which includes a pipe and a flange. The pipe includes a proximal pipe end and a flared end region. The flared end region is proximate to and continuous with the proximal pipe end, and the flange is non-integrally secured to the pipe distal to the pipe""s flared end region.
The present invention also relates to a joint assembly. The joint assembly includes a flange having an outer surface, an inner surface, and a proximal flange sealing surface end. The proximal flange sealing surface end has an annular recess therein, the inner surface includes a circumferential groove or a circumferential ridge, and the flange""s surface comprises a taper. The joint assembly further includes a backer ring having a tapered inside flange mating surface. The backer ring is disposed around the flange""s outer surface and urged proximally relative to the flange, the backer ring biases the inner surface of the flange inwardly.
The present invention relates to yet another method for sealing an end of a pipe to an external sealing surface. The method includes providing a pipe assembly which includes a pipe, a flange, and a backer ring. The pipe includes a proximal pipe end, an outer surface, and a flared end region. The flared end region is proximate to and continuous with the proximal pipe end. The flange includes an inner surface, and the flange is non-integrally disposed around the pipe distal to the pipe""s flared end region. The method further includes securing, non-integrally and distally to the pipe""s flared end region, the flange to the pipe so that proximal movement of the flange relative to the pipe is restricted. The method also includes drawing the flange toward the external sealing surface by urging the backer ring toward the external sealing surface. The drawing process causes the flange sealing surface to bias the pipe""s flared end region into sealing contact with the external sealing surface, and the urging process biases the inner surface of the flange against the outer surface of the pipe.
The present invention also relates to still another method for sealing an end of a pipe to an external sealing surface. The method includes providing a pipe assembly that includes a pipe, a flange, and a backer ring. The pipe includes a proximal pipe end, an outer surface, and a flared end region. The flared end region is proximate to and continuous with the proximal pipe end. The flange includes an inner surface and is non-integrally disposed around the pipe distal to the pipe""s flared end region. The flange is also secured, non-integrally and distally to the pipe""s flared end region, to the pipe so that proximal movement of the flange relative to the pipe is restricted. The method also includes drawing the flange toward the external sealing surface by urging the backer ring toward the external sealing surface. The drawing process causes the flange sealing surface to bias the pipe""s flared end region into sealing contact with the external sealing surface, and the urging process biases the inner surface of the flange against the outer surface of the pipe.
The present invention further relates to another pipe assembly. The pipe assembly includes a pipe which has a proximal pipe end, an outer surface, and a flared end region. The flared end region is proximate to and continuous with the proximal pipe end. The pipe assembly further includes a flange. The flange has an inner surface and is non-integrally disposed around the pipe distal to the pipe""s flared end region. The pipe assembly also includes a backer ring, which, when urged proximally relative to the pipe, biases the inner surface of the flange against the outer surface of the pipe.